The disclosure of Japanese Patent Application No. 2000-150404 filed on May 22, 2000 including the specification, drawings and abstract is incorporated herein by reference in its entirety.
1. Field of the Invention
The present invention relates to a cleaning apparatus and a cleaning method for removing foreign substances from a hydraulic circuit.
2. Description of the Related Art
Generally, in a vehicle equipped with an automatic transmission, a hydraulic control apparatus and an electronic control apparatus are provided. The hydraulic control apparatus includes a hydraulic circuit provided with oil passages for supplying and discharging oil pressure with respect to operation mechanisms of the automatic transmission, and various valves for controlling the opening and closing of the oil passages and the oil pressure in the oil passages. The electronic control apparatus is formed by a microcomputer. Various kinds of data are pre-stored in the electronic control apparatus. The electronic control apparatus is designed so that signals from various sensors and switches are inputted to the electronic control apparatus.
The electronic control apparatus makes determinations regarding the control of the transmission speed ratio based on the signals from the various sensors and switches and the aforementioned data, and outputs a control signal based on a result of the determination to the hydraulic control apparatus. As a result, the supplying/discharging of oil pressure with respect to the operational mechanisms and the oil pressure supplied thereto are controlled so as to control the speed ratio of the automatic transmission. The oil pressure supplied to the hydraulic circuit is generated by a pressure regulator device regulating the pressure ejected from an oil pump.
A hydraulic circuit as mentioned above is formed by a component part termed a xe2x80x9cvalve bodyxe2x80x9d. Such a valve body is mounted between an oil pan and a casing forming an outer shell of the automatic transmission. However, before the valve body is mounted between the casing and the oil pan, the hydraulic circuit is usually cleaned since there is a possibility of contamination of an interior of the hydraulic circuit with foreign substances.
As an art related to the hydraulic circuit cleaning apparatus as mentioned above, Japanese Patent Application Laid-Open No. HEI 10-37734 describes an example of the method for cleaning an oil supplying apparatus and a lubricant supplying apparatus used in a lubrication system of an electric power generating steam turbine, an electric power generator, etc. This laid-open patent application describes a normal-use oil pump provided in an oil tank, two oil coolers, and six nozzles that are opened and closed by an oilcooler switching valve. The patent application further describes a flushing oil pump connected to a circuit of the oil tank, and a plurality of valves for opening and closing an oil passage between the circuit and the flushing pump. Oil supplied from the normal-use oil pump is supplied to an inlet of one of the two oil coolers, and is thereby cooled. After that, oil is discharged from an outlet of the oil cooler, and is delivered to a bearing supply line. Furthermore, using oil ejected from the flushing oil pump, the oil passage in the oil tank can be cleaned.
The method of cleaning an oil supplying apparatus described in the aforementioned patent application is one in Which an oil passage provided in the oil tank is flushed. However, the patent application does not describe the cleaning of a hydraulic circuit that includes an oil pump and a pressure regulating device.
The invention has been accomplished in view of the aforementioned circumstances. The invention provides an apparatus and a method for cleaning hydraulic circuit which are capable of cleaning a hydraulic circuit that is provided with an oil pump, a pressure regulator device, etc.
A hydraulic circuit cleaning apparatus in accordance with a first mode of the invention includes a hydraulic circuit, and a discharge passage that discharges from the hydraulic circuit a cleaning liquid provided for cleaning the hydraulic circuit. The hydraulic circuit includes an oil pump, an oil passage to which an oil pressure ejected from the oil pump is supplied, and a pressure regulator device that is connected to the oil passage and that regulates the oil pressure in the oil passage. The discharge passage is connected to a discharge port of the pressure regulator device, and discharges the cleaning liquid out of the hydraulic circuit.
According to the first mode, when the cleaning liquid is delivered into the oil passage of the hydraulic circuit, the cleaning liquid is discharged into the discharge oil passage via the discharge port of the pressure regulator device. Then, the cleaning liquid is discharged from the discharge oil passage via the discharge passage. Therefore, the cleaning liquid containing foreign substances is not returned to the hydraulic circuit. Therefore, the interior of the hydraulic circuit can be cleaned by utilizing the discharge oil passage connected to the pressure regulator device.
The above-described cleaning apparatus may further include a lid member that closes the discharge passage after the hydraulic circuit is cleaned with the cleaning liquid.
If the cleaning liquid discharge passage is closed with the lid member after the hydraulic circuit is cleaned, the oil delivered into the oil passage by the oil pump will not be discharged from the cleaning liquid discharge passage.
The cleaning apparatus of the first mode may be constructed so that the oil pressure discharged from the discharge port of the pressure regulator device is supplied to the suction opening of the oil pump when the oil pump sucks the oil, provided that the discharge passage is closed with the lid member after the hydraulic circuit has been cleaned.
A hydraulic circuit cleaning apparatus in accordance with a second mode of the invention includes a hydraulic circuit, and a discharge passage that discharges from the hydraulic circuit a cleaning liquid for cleaning the hydraulic circuit. The hydraulic circuit includes an oil pump, a circulating oil passage, and a pressure regulator device disposed in the circulating oil passage for regulating the oil pressure in the oil passage. The discharge passage is connected between the pressure regulator device in the circulating oil passage and the suction opening of the oil pump, and discharges the cleaning liquid out of the hydraulic circuit.
According to the second mode, when the cleaning liquid is delivered into the oil passage of the hydraulic circuit, the cleaning liquid is delivered to the circulating oil passage, and is discharged from the discharge passage via the pressure regulator device. Therefore, the cleaning liquid contaminated with foreign substances will not be returned into the hydraulic circuit. Hence, the interior of the hydraulic circuit can be cleaned by simply utilizing the discharge oil passage connected to the pressure regulator device.
The cleaning apparatus of the second mode may further include a sealing member that closes the discharge passage, and the hydraulic circuit may further include a filtering device that filters oil sucked into the suction opening of the oil pump.
The filtering device may be constructed so as to also perform the function of preventing the plug from falling apart. In that case, it is unnecessary to provide a separate member for preventing the plug from falling apart.
In a cleaning method for cleaning a hydraulic circuit in accordance with a third mode of the invention, the hydraulic circuit includes an oil pump, an oil passage connected to a suction port of the oil pump, a pressure regulator device that is connected to the oil passage and that regulates the oil pressure in the oil passage, and a discharge oil passage connecting a discharge port of the pressure regulator device and the suction port of the oil pump, and the cleaning liquid used to clean the hydraulic circuit is discharged via the discharge oil passage.
According to the third mode, the cleaning liquid used to clean the hydraulic circuit is discharged out of the hydraulic circuit via the discharge oil passage. Therefore, the method prevents the cleaning liquid contaminated with foreign substances from circulating in the hydraulic circuit. Hence, the method makes it possible to clean the interior of the hydraulic circuit by using the discharge oil passage connected to the pressure regulator device.